1. What happened
Attached project reports value returned by Profiler.GetTotalAllocatedMemoryLong(). That value steadily increasing. Happens only in Editor and not in Player (tried also with Player dev mode). The same happens if turning the UI off, reporting the values only to console with Debug.Log.
Opening other Editor windows show immediate memory increase. The most obvious one is Profiler - after opening it memory usage would 'jump' by ~7 MB and won't go down after the window is closed, continuing to grow.
I was leaving the Editor running for about an hour and the behaviour didn't change - steady growth continues.
Haven't witnessed any side effects of it though.

2. How we can reproduce it using the example you attached
- Scene 1
- Play
>>> Observe that 'Total allocated' is increasing
- Open Profiler
>>> Total increased by ~7 MBs
- Close Profiler
>>> Memory remains at about the same level and continues to grow.

This is a regression from 5.6.3f1.